1. Field of the Invention
The present invention relates to a motor-driven-type injection molding machine in which an injection apparatus and a mold clamping apparatus are disposed on the upper surface of a machine base.
2. Description of the Related Art
Conventionally, a motor-driven-type injection molding machine in which servomotors are used as drive sources has been known (see, for example, Japanese Patent Application Laid-Open (kokai) No. 9(1997)-11290.
Such a motor-driven-type injection molding machine comprises a screw reciprocation drive section and a screw rotation drive section. In the screw reciprocation drive section, a servomotor for screw reciprocation is attached to a motor attachment member disposed on the upper surface of a machine base; a screw portion of a ball-screw mechanism connected to a motor shaft of the servomotor is screw-engaged with a nut portion provided on a slider which is supported to be movable in the front/rear direction; and a screw is rotatably supported at the front end of the slider. Thus, the screw is advanced and retracted upon rotation of the servomotor for screw reciprocation. In the screw rotation drive section, a servomotor for screw rotation is attached to the slider; and a driver gear attached to a motor shaft of the servomotor is meshed with a driven gear provided on a shaft portion of the screw. Thus, the screw is rotated upon rotation of the servomotor for screw rotation.
The above-described conventional motor-driven-type injection molding machine has the following drawbacks to be solved.
First, since the servomotors must be disposed in the vicinity of the respective portions to which rotation is transmitted (hereinafter referred to as "rotation-transmitted portions"), the servomotors--which are heavy and large in size--care disposed at upper and side portions of the molding machine. Therefore, the molding machine suffers a weight imbalance (i.e., is topheavy), so that transportation and installation of the molding machine cannot be performed in a stable manner.
Second, the servomotors are disposed at a position close to an operator area in an exposed state, and means for insulating motor noise is not provided. Therefore, the operator is exposed to excessive motor noise, so that the molding machine is unsatisfactory in terms of quietness.
Third, since a control unit for the servomotors is typically accommodated within the machine base, connection cords for connecting the control unit and the servomotors become long and are exposed to the outside, resulting in occurrence of various problems such as a problem of an object becoming entangled in the connection cords.